Even at our current levels eCO2 is harming our health: Rising CO2, Climate Change, and Public Health: Exploring the Links to Plant Biology https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649213/ these are direct CO2 effects on plant physiology leading to negative human outcomes.
eCO2 has dozens of negative effect on natural (and engineered systems including concrete chemistry) systems (inc. us). There are no positives that I've seen yet.
Dang?
> You were born at 0.0xyz% CO2, It is now 0.0abc% CO2
instead of using PPM would be less alarming.